The teams' opening bout in Italy ended with Inter taking the slimmest of advantages, but they have since continued some inconsistent form while their hosts are now back in the habit of winning.
Match preview
A frustrating night at San Siro resulted in defeat for Porto last month, with Inter substitute Romelu Lukaku scoring the only goal as Sergio Conceicao's 10-man side lost the first game of their latest adventure in the Champions League knockout stage.
Defying his recent fortunes in front of goal, Lukaku converted the rebound after hitting the post with 85 minutes on the clock, not long after Otavio was sent off for a second booking - the midfielder's first was for dissent and a foul on Hakan Calhanoglu later saw him dismissed.
Portugal's Primeira Liga champions had already been denied by Inter goalkeeper Andre Onana on a couple of occasions, but failing to find a breakthrough in Milan leaves them facing a must-win situation in Tuesday's return.
Losing has become an unfamiliar feeling this season for the Dragoes, as in addition to winning their last four fixtures to finish first in Group B before the winter break they had won 10 straight matches prior to slipping up at San Siro.
Sensationally beaten at home by Gil Vicente just four days after that setback, normal service has since been resumed and Porto have beaten both Chaves and Estoril over the past fortnight, scoring six times in the process.
The latter result was a close call, as only a Mehdi Taremi penalty sealed the points on Friday, and they trail a relentless Benfica side already qualified for the Champions League quarter-finals by five points, having also played a game more.
Inter may have ended their 22-match unbeaten streak in the first leg, but Porto progressed from their two most recent last-16 ties - both in 2019 and 2021. While the defence of their 2004 title ended with a 4-2 aggregate loss to the Nerazzurri at this stage, given their visitors' recent failings, the Dragoes will expect to overturn their deficit.
In the Champions League knockout phase for the second year running, Inter's journey last season ended in defeat to Liverpool, but Simone Inzaghi's side beat Barcelona to finish second in Group C during the autumn and are now 90 minutes away from a place in the last eight.
Having won the first leg for only the second time in their last 10 attempts at this stage, the Italian giants will aim to continue a trend of finishing the job in Europe's premier club competition: they have won four of their last seven away games in the elimination stage, with all four coming in second legs.
Indebted to Onana and grateful for an increasingly rare Lukaku goal at San Siro, Inter have suffered more indifferent results on their travels of late, as a goalless draw with struggling Sampdoria was followed by a 1-0 loss in Bologna before another failure last Friday.
Serie A leaders Napoli hold a huge 18-point lead over the 2020-21 champions following an eighth league defeat of the season for Inzaghi's men, and a sixth setback on the road - on this occasion, at lowly Spezia - leaves them with just the seventh-best away record in Italy's top flight.
Precedent is not on the Nerazzurri's side either, as they have won just one of their eight matches away to Portuguese sides in UEFA competitions, losing on each of their last two visits - though not since September 2006 versus Sporting.
Embroiled in a five-way battle for three spots below Napoli in the race to qualify for next season's Champions League, Inter also have a Coppa Italia semi-final tie against old foes Juventus to tackle next month, but they would first love to put a halt to their away-day blues and book a place in the Champions League quarter-finals.
Porto Champions League form:
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Porto form (all competitions):
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Inter Milan Champions League form:
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Inter Milan form (all competitions):
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Team News
As Otavio misses out due to suspension after his red card in Milan, Andre Franco and Stephen Eustaqio are among those in contention for selection, with Sergio Conceicao having to make at least one change to the side that started the first leg.
Despite sustaining a heel injury against Estoril, Canada international Eustaquio should be fit to offer a more conservative option, while both Franco and Galeno - the latter of whom returned to the bench on Friday - provide more attacking potential. Galeno's fellow Brazilian Evanilson is still struggling with a thigh problem.
Conceicao should revert to a more familiar lineup on Tuesday, with Mehdi Taremi and Matheus Uribe both back from the start after being benched at the weekend.
Inter goalkeeper Andre Onana will also return after being rested on Friday, following more criticism of club captain Samir Handanovic for his performance in La Spezia.
Setting up in Simone Inzaghi's preferred 3-5-2, the visitors will bring in Hakan Calhanoglu and Federico Dimarco, but a two-way tussle between Edin Dzeko and Romelu Lukaku to join top scorer Lautaro Martinez up front remains undecided.
Joaquin Correa is another option following his recent return to training but could appear as a second-half substitute at best, while Milan Skriniar may not make the squad due to a back problem - Sunday's Derby D'Italia is a more likely target for the Slovakian defender.
Porto possible starting lineup:
Costa; Mario, Pepe, Cardoso, Sanusi; Grujic, Uribe; Franco, Pepe, Galeno; Taremi
Inter Milan possible starting lineup:
Onana; De Vrij, Acerbi, Bastoni; Dumfries, Barella, Calhanoglu, Mkhitaryan, Dimarco; Martinez, Lukaku